Access ports are widely used in medical procedures to gain access to anatomical cavities ranging in size from the abdomen to small blood vessels, such as veins and arteries, epidural, pleural and subarachnoid spaces, heart ventricles, and spinal and synovial cavities. The use of access ports has become common as they provide minimally invasive techniques for establishing a portal for a number of procedures, such as those involving the abdominal cavity. Reduced postoperative recovery time, markedly decreased post-operative pain and wound infection, and improved cosmetic outcome are well established benefits of minimally invasive surgery, derived mainly from the ability of surgeons to perform an operation utilizing smaller incisions of the body cavity wall.
A trocar is one type of access port that is commonly used to provide a minimally invasive pathway for accessing a surgical site. Trocars generally include a cutting assembly or obturator that is disposed within an outer cannula. The sharp distal end of the cutting assembly, with the cannula disposed therearound, is urged through the skin until it enters the anatomical cavity being penetrated. Because the umbilicus is well-hidden and the thinnest and least vascularized area of the abdominal wall, the umbilicus is generally a preferred choice of abdominal cavity entry in laparoscopic procedures. Further, an umbilical incision can be easily enlarged (in order to eviscerate a larger specimen) without significantly compromising cosmesis and without increasing the chances of wound complications. The abdominal cavity is typically insufflated with CO2 gas to a pressure of around 15 mm Hg. The cutting assembly is then withdrawn from the cannula, which remains in place to provide a passageway through which access to the anatomical cavity is provided for other surgical devices, e.g., laparoscopic instruments such as graspers, dissectors, scissors, retractors, etc.
One drawback of current trocars is that they inhibit movement of surgical instruments inserted therethrough, due to the long, rigid, and narrow lumen defined therein. As a result, a surgeon must tilt the entire rigid access device in order manipulate the instruments, while avoiding damage to non-target organs of the abdominal cavity. Further, such devices can be accidentally moved and/or removed during surgery, which could affect insufflation as well as interfere with proper positioning of the instruments.
Accordingly, there remains a need for improved instruments and trocar systems.